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'use strict';
const Joi = require('joi');
const Pify = require('pify');
const Redis = require('redis');
const UUID = require('uuid/v4');
const internals = {};
internals.kPostsPrefix = 'posts';
internals.kMaxPostSize = 255;
internals.kPostsSchema = Joi.object().keys({
uuid: Joi.string().required(),
content: Joi.string().max(internals.kMaxPostSize).required(),
timestamp: Joi.number().integer().required(),
userId: Joi.string().required(),
userName: Joi.string().required(),
userImage: Joi.string().required()
});
/**
* Handles the HTTP requests for posts related operations
*
* @class PostsHandler
* @param {Dasein.tConfiguration} config The configuration to
* initialize.
*/
module.exports = internals.PostsHandler = class PostsHandler {
constructor(config) {
this._ttl = config.ttl;
this._redis = Redis.createClient(config.redis);
// Log an error if it happens.
this._redis.on('error', (err) => {
console.error(err);
});
}
/**
* Fetches all available posts
*
* @function findAll
* @memberof PostsHandler
* @instance
* @return {generator} a koa compatible handler generator function
*/
findAll() {
const self = this;
return function * () {
if (!this.state.user) {
return this.throw('Unauthorized', 401);
}
const scan = Pify(self._redis.scan.bind(self._redis));
const hgetall = Pify(self._redis.hgetall.bind(self._redis));
let keys = [];
let nextCursor = 0;
let currentKeys = null;
do {
[nextCursor, currentKeys] = yield scan(nextCursor || 0, 'MATCH', `${internals.kPostsPrefix}:*`);
keys = keys.concat(currentKeys);
} while (nextCursor > 0);
const posts = yield keys.map((key) => hgetall(key));
this.body = posts.sort((a, b) => b.timestamp - a.timestamp);
};
}
/**
* Fetches a single post
*
* @function find
* @memberof PostsHandler
* @instance
* @return {generator} a koa compatible handler generator function
*/
find() {
const self = this;
return function * (uuid) {
if (!this.state.user) {
return this.throw('Unauthorized', 401);
}
const hgetall = Pify(self._redis.hgetall.bind(self._redis));
const postKey = `${internals.kPostsPrefix}:${uuid}`;
const post = yield hgetall(postKey);
if (!post) {
this.throw('Post not found', 404);
}
this.body = post;
};
}
/**
* Creates a post
*
* @function create
* @memberof PostsHandler
* @instance
* @return {generator} a koa compatible handler generator function
*/
create() {
const self = this;
return function * () {
if (!this.state.user) {
return this.throw('Unauthorized', 401);
}
const hmset = Pify(self._redis.hmset.bind(self._redis));
const hgetall = Pify(self._redis.hgetall.bind(self._redis));
const expire = Pify(self._redis.expire.bind(self._redis));
const uuid = UUID();
const timestamp = Date.now();
const user = this.state.user;
const postKey = `${internals.kPostsPrefix}:${uuid}`;
const post = {
uuid,
content: this.request.body.content,
timestamp,
userId: user.screen_name,
userName: user.name,
userImage: user.profile_image_url_https
};
yield self._validate(post).catch((err) => {
this.throw(err.message, 422);
});
yield hmset(postKey, post);
yield expire(postKey, self._ttl);
this.body = yield hgetall(postKey);
};
}
/**
* Deletes a post
*
* @function delete
* @memberof PostsHandler
* @instance
* @return {generator} a koa compatible handler generator function
*/
delete() {
return function * () {};
}
// Validates the post schema
_validate(post) {
const validate = Pify(Joi.validate.bind(Joi));
return validate(post, internals.kPostsSchema);
}
};
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